Amount of current and voltage in an average shock from a door nob?

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Discussion Overview

The discussion revolves around the amount of current and voltage experienced during an electric shock from a door knob or handle, particularly in the context of electrostatic discharge (ESD). Participants explore the characteristics of such shocks, including their intensity and duration, as well as comparisons to other electrical stimuli like electrical muscle stimulation (EMS).

Discussion Character

  • Exploratory
  • Technical explanation
  • Debate/contested

Main Points Raised

  • One participant inquires about the specific current and voltage levels associated with a typical shock from a door knob, expressing difficulty in finding this information.
  • Another participant references the EN 61000-4-2 ESD test standard, noting that a shock felt would likely require a voltage of at least a couple of kV, with peak currents potentially reaching a couple hundred amps, but with very short duration resulting in low energy.
  • A participant questions whether the current felt during such shocks could be in the range of hundreds of milliamps, expressing concern about the potential lethality of such currents, especially in comparison to the maximum current used in EMS.
  • It is mentioned that the transient nature of the current, lasting about a nanosecond, differentiates it from more sustained currents that can be harmful.
  • A personal anecdote is shared about experiencing a 10kV air discharge, emphasizing the discomfort and potential risks associated with high-voltage static shocks.
  • Another participant reassures that typical static shocks encountered in daily life are usually in the range of a kV or two, rather than more dangerous levels.

Areas of Agreement / Disagreement

Participants express varying views on the intensity of the shock felt from a door knob, particularly regarding the current levels and their potential dangers. There is no consensus on the exact values or implications of the shocks discussed.

Contextual Notes

The discussion includes assumptions about the nature of electrical shocks and their effects, as well as dependencies on specific testing standards and conditions. The transient nature of the current and its implications for safety are also highlighted but remain unresolved.

wushumaster
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Amount of current and voltage in an average "shock" from a door nob?

What is the amount of current and voltage in an average "shock" from a door nob/handle? I have looked everywhere and cannot seem to find it! Please help!
Thanks
 
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wushumaster said:
What is the amount of current and voltage in an average "shock" from a door nob/handle? I have looked everywhere and cannot seem to find it! Please help!
Thanks

The common ESD test standard is EN 61000-4-2, and the test devices that you use to zap the equipment under test (to be sure they will be reliable in the real world) use an output circuit of 150pF in series with a 330 Ohm output resistor for air discharge testing. The rise time of the output discharge is on the order of 1ns.

For you to feel the shock, it would need to be at least a couple of kV. The peak currents are high (a couple hundred amps I think but I'm not sure about that), but the duration is so small that there is not much energy behind it. 10kV stored on 150pF is only 7.5mJ.
 


But we typically feel at least a small shock, right? So since current dominated what we "feel" are you saying that we would feel 100s of mA? Because I thought that kind of current has the potential to kill us. Electrical muscle stimulation max current is only 64 mA.
I'm trying to put in perspective for the IRB that the shock from EMS is not that big/ bad...
 


wushumaster said:
But we typically feel at least a small shock, right? So since current dominated what we "feel" are you saying that we would feel 100s of mA? Because I thought that kind of current has the potential to kill us. Electrical muscle stimulation max current is only 64 mA.
I'm trying to put in perspective for the IRB that the shock from EMS is not that big/ bad...

But as I said, this transient current only lasts for about a nanosecond. That's the difference.

Still, I've managed to shock myself accidentally during product ESD testing, and it's no fun at all. And I've accidentally taken about a 10kV air discharge from arm-to-arm (the worst way), and I could feel my heart not appreciating it at all. Luckily, most static shocks that you feel in normal life are just a kV or two, and not typically arm-to-arm.
 

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